Greeting, FYI, we noticed the following commit (built with gcc-7): commit: 63f818f46af9f8b3f17b9695501e8d08959feb60 ("proc: Use a dedicated lock in struct pid") https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git master in testcase: rcuperf with following parameters: runtime: 300s perf_type: tasks on test machine: qemu-system-i386 -enable-kvm -cpu SandyBridge -smp 2 -m 8G caused below changes (please refer to attached dmesg/kmsg for entire log/backtrace): If you fix the issue, kindly add following tag Reported-by: kernel test robot [ 2.435926] WARNING: held lock freed! [ 2.435926] 5.6.0-rc2-00029-g63f818f46af9f #2 Not tainted [ 2.435926] ------------------------- [ 2.435926] cryptomgr_test/87 is freeing memory 4022b180-4022b6cb, with a lock still held there! [ 2.435926] 4022b190 (&(&sighand->siglock)->rlock){....}, at: release_task+0x1db/0x9c0 [ 2.435926] 1 lock held by cryptomgr_test/87: [ 2.435926] #0: 42708054 (tasklist_lock){....}, at: release_task+0xc5/0x9c0 [ 2.435926] [ 2.435926] stack backtrace: [ 2.435926] CPU: 0 PID: 87 Comm: cryptomgr_test Not tainted 5.6.0-rc2-00029-g63f818f46af9f #2 [ 2.435926] Call Trace: [ 2.435926] ? dump_stack+0x14d/0x1da [ 2.435926] ? debug_check_no_locks_freed+0x285/0x2a0 [ 2.435926] ? slab_free_freelist_hook+0x118/0x270 [ 2.435926] ? kmem_cache_free+0xb4/0x710 [ 2.435926] ? lock_release+0x194/0x600 [ 2.435926] ? __cleanup_sighand+0xdf/0x120 [ 2.435926] ? release_task+0x555/0x9c0 [ 2.435926] ? do_exit+0xf79/0x1900 [ 2.435926] ? __module_put_and_exit+0x1d/0x20 [ 2.435926] ? cryptomgr_test+0x4c/0x50 [ 2.435926] ? kthread+0x192/0x1d0 [ 2.435926] ? crypto_unregister_scomps+0x60/0x60 [ 2.435926] ? kthread_bind+0x50/0x50 [ 2.435926] ? ret_from_fork+0x19/0x24 [ 2.444324] ACPI: Added _OSI(Module Device) [ 2.444854] ACPI: Added _OSI(Processor Device) [ 2.444975] ACPI: Added _OSI(3.0 _SCP Extensions) [ 2.445500] ACPI: Added _OSI(Processor Aggregator Device) [ 2.445945] ACPI: Added _OSI(Linux-Dell-Video) [ 2.446410] ACPI: Added _OSI(Linux-Lenovo-NV-HDMI-Audio) [ 2.446943] ACPI: Added _OSI(Linux-HPI-Hybrid-Graphics) [ 2.450868] ACPI: 1 ACPI AML tables successfully acquired and loaded [ 2.454130] ACPI: Interpreter enabled [ 2.454564] ACPI: (supports S0 S3 S5) [ 2.454919] ACPI: Using IOAPIC for interrupt routing [ 2.455006] PCI: Using host bridge windows from ACPI; if necessary, use "pci=nocrs" and report a bug [ 2.456393] ACPI: Enabled 2 GPEs in block 00 to 0F [ 2.471162] ACPI: PCI Root Bridge [PCI0] (domain 0000 [bus 00-ff]) [ 2.471813] acpi PNP0A03:00: _OSC: OS supports [Segments HPX-Type3] [ 2.471986] acpi resource window ([0x240000000-0x2bfffffff] ignored, not CPU addressable) [ 2.472903] PCI host bridge to bus 0000:00 [ 2.472954] pci_bus 0000:00: root bus resource [io 0x0000-0x0cf7 window] [ 2.473583] pci_bus 0000:00: root bus resource [io 0x0d00-0xffff window] [ 2.473946] pci_bus 0000:00: root bus resource [mem 0x000a0000-0x000bffff window] [ 2.474651] pci_bus 0000:00: root bus resource [mem 0xc0000000-0xfebfffff window] [ 2.474947] pci_bus 0000:00: root bus resource [bus 00-ff] [ 2.475532] pci 0000:00:00.0: [8086:1237] type 00 class 0x060000 [ 2.476874] pci 0000:00:01.0: [8086:7000] type 00 class 0x060100 [ 2.477793] pci 0000:00:01.1: [8086:7010] type 00 class 0x010180 [ 2.482961] pci 0000:00:01.1: reg 0x20: [io 0xc200-0xc20f] [ 2.485679] pci 0000:00:01.1: legacy IDE quirk: reg 0x10: [io 0x01f0-0x01f7] [ 2.485948] pci 0000:00:01.1: legacy IDE quirk: reg 0x14: [io 0x03f6] [ 2.486592] pci 0000:00:01.1: legacy IDE quirk: reg 0x18: [io 0x0170-0x0177] [ 2.486945] pci 0000:00:01.1: legacy IDE quirk: reg 0x1c: [io 0x0376] [ 2.488270] pci 0000:00:01.3: [8086:7113] type 00 class 0x068000 [ 2.489277] pci 0000:00:01.3: quirk: [io 0x0600-0x063f] claimed by PIIX4 ACPI [ 2.489955] pci 0000:00:01.3: quirk: [io 0x0700-0x070f] claimed by PIIX4 SMB [ 2.491330] pci 0000:00:02.0: [1234:1111] type 00 class 0x030000 [ 2.494029] pci 0000:00:02.0: reg 0x10: [mem 0xfd000000-0xfdffffff pref] [ 2.498032] pci 0000:00:02.0: reg 0x18: [mem 0xfebf0000-0xfebf0fff] [ 2.508036] pci 0000:00:02.0: reg 0x30: [mem 0xfebe0000-0xfebeffff pref] [ 2.509926] pci 0000:00:03.0: [8086:100e] type 00 class 0x020000 [ 2.511874] pci 0000:00:03.0: reg 0x10: [mem 0xfebc0000-0xfebdffff] [ 2.513875] pci 0000:00:03.0: reg 0x14: [io 0xc000-0xc03f] [ 2.521883] pci 0000:00:03.0: reg 0x30: [mem 0xfeb80000-0xfebbffff pref] [ 2.522797] pci 0000:00:04.0: [1af4:1001] type 00 class 0x010000 [ 2.524954] pci 0000:00:04.0: reg 0x10: [io 0xc040-0xc07f] [ 2.527972] pci 0000:00:04.0: reg 0x14: [mem 0xfebf1000-0xfebf1fff] [ 2.534968] pci 0000:00:04.0: reg 0x20: [mem 0xfe000000-0xfe003fff 64bit pref] [ 2.538075] pci 0000:00:05.0: [1af4:1001] type 00 class 0x010000 [ 2.539953] pci 0000:00:05.0: reg 0x10: [io 0xc080-0xc0bf] [ 2.542965] pci 0000:00:05.0: reg 0x14: [mem 0xfebf2000-0xfebf2fff] [ 2.549967] pci 0000:00:05.0: reg 0x20: [mem 0xfe004000-0xfe007fff 64bit pref] [ 2.554040] pci 0000:00:06.0: [1af4:1001] type 00 class 0x010000 [ 2.556967] pci 0000:00:06.0: reg 0x10: [io 0xc0c0-0xc0ff] [ 2.558955] pci 0000:00:06.0: reg 0x14: [mem 0xfebf3000-0xfebf3fff] [ 2.565961] pci 0000:00:06.0: reg 0x20: [mem 0xfe008000-0xfe00bfff 64bit pref] [ 2.570014] pci 0000:00:07.0: [1af4:1001] type 00 class 0x010000 [ 2.572962] pci 0000:00:07.0: reg 0x10: [io 0xc100-0xc13f] [ 2.574970] pci 0000:00:07.0: reg 0x14: [mem 0xfebf4000-0xfebf4fff] [ 2.582964] pci 0000:00:07.0: reg 0x20: [mem 0xfe00c000-0xfe00ffff 64bit pref] [ 2.585992] pci 0000:00:08.0: [1af4:1001] type 00 class 0x010000 [ 2.588959] pci 0000:00:08.0: reg 0x10: [io 0xc140-0xc17f] [ 2.590953] pci 0000:00:08.0: reg 0x14: [mem 0xfebf5000-0xfebf5fff] [ 2.597965] pci 0000:00:08.0: reg 0x20: [mem 0xfe010000-0xfe013fff 64bit pref] [ 2.602029] pci 0000:00:09.0: [1af4:1001] type 00 class 0x010000 [ 2.603959] pci 0000:00:09.0: reg 0x10: [io 0xc180-0xc1bf] [ 2.605988] pci 0000:00:09.0: reg 0x14: [mem 0xfebf6000-0xfebf6fff] [ 2.611965] pci 0000:00:09.0: reg 0x20: [mem 0xfe014000-0xfe017fff 64bit pref] [ 2.615881] pci 0000:00:0a.0: [1af4:1001] type 00 class 0x010000 [ 2.617848] pci 0000:00:0a.0: reg 0x10: [io 0xc1c0-0xc1ff] [ 2.618947] pci 0000:00:0a.0: reg 0x14: [mem 0xfebf7000-0xfebf7fff] [ 2.625967] pci 0000:00:0a.0: reg 0x20: [mem 0xfe018000-0xfe01bfff 64bit pref] [ 2.629890] pci 0000:00:0b.0: [8086:25ab] type 00 class 0x088000 [ 2.630952] pci 0000:00:0b.0: reg 0x10: [mem 0xfebf8000-0xfebf800f] [ 2.638530] pci_bus 0000:00: on NUMA node 0 [ 2.640636] ACPI: PCI Interrupt Link [LNKA] (IRQs 5 *10 11) [ 2.642160] ACPI: PCI Interrupt Link [LNKB] (IRQs 5 *10 11) [ 2.643153] ACPI: PCI Interrupt Link [LNKC] (IRQs 5 10 *11) [ 2.644153] ACPI: PCI Interrupt Link [LNKD] (IRQs 5 10 *11) To reproduce: # build kernel cd linux cp config-5.6.0-rc2-00029-g63f818f46af9f .config make HOSTCC=gcc-7 CC=gcc-7 ARCH=i386 olddefconfig prepare modules_prepare bzImage git clone https://github.com/intel/lkp-tests.git cd lkp-tests bin/lkp qemu -k job-script # job-script is attached in this email Thanks, Rong Chen